1. Field of the Invention
The invention relates to the field of cross-country ski boots and related footwear.
2. Description of Background and Relevant Information
The expression cross-country skiing, at least as used herein, refers not only to cross-country skiing, but to its direct derivative, back-country skiing, which requires the use of similar equipment, devices, although the binding devices are typically larger than those used in the more traditional cross-country skiing, in order to withstand greater forces/pressures, and the boots are higher and generally provide greater warmth. These ski-related sports are different from alpine skiing or telemark skiing in that they are practiced on terrain that is not particularly rugged and can be practiced with boots having flexible soles.
The documents EP-913103 and U.S. Pat. No. 6,289,610 disclose a sole for a sports footwear, particularly for cross-country skiing, which includes two members for connecting the boot to a binding of a cross-country ski. In the examples disclosed in these documents, each of the connecting members, or connectors, is independently anchored in the sole. To this end, they each include anchoring portions onto which the sole is directly overmolded. This anchoring system works perfectly insofar as the material used to make the sole has good mechanical properties, particularly in terms of tensile strength in traction, in order to prevent the connecting members from being separated during use. Thus, this anchoring system works well with materials having a tensile strength in traction greater than about 30-35 MPa.
With products of lower performance (but which are, for example less costly to manufacture, easier to implement, and/or have better adherence properties), the risk of separation of the connecting members from the sole increases substantially.
The document U.S. Pat. No. 4,907,353 discloses a solution, which makes it possible to avoid any risk of separation from the connecting member. The connecting member, or “hooking element,” is anchored in a massive anchoring element made of a hard resistant material and overmolded with the material of the sole.
Another solution is disclosed in the document FR-2645038 in which the connecting member is fixed to an anchoring element in the shape of a metal plate on which the material of the sole is overmolded.
The solutions described in the aforementioned two documents are interesting but cannot be transferred to a sole provided with two connecting members, rather than one. Indeed, as shown in the document EP-913103 mentioned above, to make a cross-country ski boot, one having ordinary skill in the art seeks to preserve as much flexibility as possible for the sole in the location that corresponds to the metatarsophalangeal articulation zone of the skier's foot, as well as in the area between the front of this zone and the front end of the sole. This flexibility is required to ensure a proper boot rolling movement, i.e., a movement which might be said to simulate the natural movement of the foot during movement. Therefore, the solutions described above are valid when the connecting member is anchored at the very front end of the sole, but would not be valid if they were directly transposed to anchoring a connecting member, or a pair of such members, located further toward the rear, particularly at the metatarsophalangeal zone, or slightly forward of such zone.